wouldn't it be more fun if the monsters/undead came in waves? like with wave one easy, wave 2 medium, wave 3 hard, wave 4 very hard.
With 1 as the most common type of wave and 4 the rarest.
realms would have perhaps a whole month of nothing and then suddenly 2 weeks long struggling large waves of monsters, sometimes even building up wave after wave.
because there is so much wilderness in Dwilight, some small monsters/undead might travel in plundering bands, seeking out the richer regions, thus realms.
this of course for Dwilight only.
Quite radical but fun.